The SS United States, the historic luxury ocean liner that has languished for decades and seemed destined for the scrap heap, could again take to the seas under a proposal unveiled Thursday in New York City.

Crystal Cruises announced an exclusive purchase option for the ocen liner, valid for nine months and pending a feasibility study, to restore the ship to its former grandeur at an estimated cost of $700-800 million, reported news agency AFP.

"It will be a very challenging undertaking," the cruise line's CEO Edie Rodriguez said at a press conference, calling it a "monumental project" for an "important symbol of America."

The SS United States was the fastest, most luxurious ocean liner of its day, with a capacity of 2,000 passengers who were entertained by three orchestras, two cinemas and a swimming pool.

On its maiden voyage on July 3, 1952, the 990-foot ocean liner crossed the Atlantic in a record three days, 10 hours and 40 minutes. The record still stands.

During its lifetime, the boat ferried one million passengers between the U.S. and Europe, including celebrities such as Marilyn Monroe, Coco Chanel, Marlon Brando and four US presidents.

But it was decommissioned in 1969 due to the growing popularity of air travel.

The SS United States has changed hands several times since then with various ideas of turning it into a casino, a cruise liner or a hospital ship, but none came to fruition.

Five years ago, the empty rusty boat with peeling paint was bought by the non-profit group SS United States Conservancy.

That group warned in October that the ship would have to be sold to a scrapyard unless new funds or investors came forward to cover the $60,000 a month it cost to dock the ship in the Delaware River in Philadelphia.

Rodriguez said if the feasibility study is successful, then the goal is for the renovated SS United States to begin ocean cruises again in 2018.

The proposal presented Thursday would maintain some of the ship's features of yore, such as its red smokestacks and the promenade, but it will be completely transformed to accommodate 400 luxury suites for 800 passengers.

Susan Gibbs, director of the SS United States Conservancy and granddaughter of the boat's architect, expressed her approval of the Crystal Cruises plan.

The SS United States, the historic luxury ocean liner that has languished for decades and seemed destined for the scrap heap, could again take to the seas under a proposal unveiled Thursday in New York City.